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1.
Aging Ment Health ; 27(12): 2490-2498, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37116186

RESUMO

Objectives: The COVID-19 pandemic brought ageism to the forefront of public discourse. Negative ageism incurs more negative self-perceptions of aging, which affects physical and mental functioning. Whether negative ageism as perceived and experienced by older adults has worsened as the pandemic lingered, and how such changes impact quality of life (QoL) and mental well-being (MWB), remain urgent questions.Method: In a sample of adults aged 55 or older (n = 500), we aimed to address this by administering the Perceived Ageism Questionnaire twice during the pandemic (T1: between October 2020 and May 2021; T2: on average 45 wk after T1).Results: Higher levels of perceived negative ageism were associated with lower QoL and MWB, at least partially through its unfavorable effects on self-perceptions of aging, even after controlling for ageism experiences in the preceding year (at T2, corrected for T1). Furthermore, we found that perceived negative ageism increased from T1 to T2, which had negative implications for QoL/MWB. Opposite effects were found for perceived positive ageism, although less consistently.Conclusion: These patterns reveal that ageism as perceived and experienced by adults of 55 or older became stronger and more negative throughout the COVID-19 pandemic, which had detrimental implications for individuals' QoL and MWB. These disconcerting findings emphasize the importance of combatting negative ageism in our society.

2.
Appetite ; 96: 560-571, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26482282

RESUMO

Adolescents and children are the targets of much food advertising, the majority of which is for unhealthy snacks. Although the effects of advertising on food preferences and consummatory behavior are well documented, our understanding of the underlying mechanisms is still limited. The present study investigates an associative (ideomotor) mechanism by which exposure to rewarding (snack) outcomes may activate behavior that previously resulted in these rewards. Specifically, we used a computerized task to investigate whether exposing adolescents to food pictures directly, or to Pavlovian cues predictive of those food pictures, would bias their subsequent responses towards the presented/signaled food. Furthermore, we assessed whether this effect was particularly pronounced with palatable, high-calorie snacks (crisps and chocolate) relative to low-calorie snacks (tomatoes and cucumber). In two experiments, adolescents learnt that certain key presses would yield particular food pictures - some high calorie and others low calorie - before learning Pavlovian associations between cues (cartoon monsters) and these same food pictures. Subsequently, in a response-priming test, we examined the extent to which the food pictures and Pavlovian cues spontaneously primed the previously associated response. The results show that we replicated, in adolescents, previous demonstrations of ideomotor response priming in adults: food pictures biased responding towards the response that previously yielded them, and this effect transferred to the Pavlovian cues. Furthermore, the priming effect was significantly stronger for high-calorie rewards than for low-calorie. These findings indicate that the ideomotor mechanism plays an important role in the detrimental effect of our obesogenic environment, with its plethora of unhealthy food reminders, on adolescents' food-related choices.


Assuntos
Comportamento de Escolha , Meio Ambiente , Preferências Alimentares/psicologia , Adolescente , Índice de Massa Corporal , Sinais (Psicologia) , Ingestão de Energia , Comportamento Alimentar/psicologia , Feminino , Humanos , Fome , Masculino , Obesidade Infantil/epidemiologia , Fatores Sexuais , Lanches , Inquéritos e Questionários
3.
Brain Cogn ; 101: 17-34, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26554843

RESUMO

The inhibition of impulsive response tendencies that conflict with goal-directed action is a key component of executive control. An emerging literature reveals that the proficiency of inhibitory control is modulated by expected or unexpected opportunities to earn reward or avoid punishment. However, less is known about how inhibitory control is impacted by the processing of task-irrelevant stimulus information that has been associated previously with particular outcomes (reward or punishment) or response tendencies (action or inaction). We hypothesized that stimulus features associated with particular action-valence tendencies, even though task irrelevant, would modulate inhibitory control processes. Participants first learned associations between stimulus features (color), actions, and outcomes using an action-valence learning task that orthogonalizes action (action, inaction) and valence (reward, punishment). Next, these stimulus features were embedded in a Simon task as a task-irrelevant stimulus attribute. We analyzed the effects of action-valence associations on the Simon task by means of distributional analysis to reveal the temporal dynamics. Learning patterns replicated previously reported biases; inherent, Pavlovian-like mappings (action-reward, inaction-punishment avoidance) were easier to learn than mappings conflicting with these biases (action-punishment avoidance, inaction-reward). More importantly, results from two experiments demonstrated that the easier to learn, Pavlovian-like action-valence associations interfered with the proficiency of inhibiting impulsive actions in the Simon task. Processing conflicting associations led to more proficient inhibitory control of impulsive actions, similar to Simon trials without any association. Fast impulsive errors were reduced for trials associated with punishment in comparison to reward trials or trials without any valence association. These findings provide insight into the temporal dynamics of task irrelevant information associated with action and valence modulating cognitive control. We discuss putative mechanisms that might explain these interactions.


Assuntos
Aprendizagem por Associação/fisiologia , Cognição/fisiologia , Função Executiva/fisiologia , Inibição Psicológica , Tempo de Reação/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Punição , Recompensa , Adulto Jovem
4.
Cogn Affect Behav Neurosci ; 14(2): 647-58, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24796599

RESUMO

According to dual-system theories, instrumental learning is supported by dissociable goal-directed and habitual systems. Previous investigations of the dual-system balance in healthy aging have yielded mixed results. To further investigate this issue, we compared performance of young (17-24 years) and older (69-84 years) adults on an instrumental learning task. Following the initial learning phase, the behavioral autonomy of the motivational significance of the instrumental outcome was assessed with an outcome-devaluation test and slips-of-action test. The present study provides evidence for a disrupted dual-system balance in healthy aging, as reflected in reduced outcome-induced conflict during acquisition, as well as in impaired performance during the test stage, during which participants had to flexibly adjust their actions to changes in the current desirability of the behavioral outcome. These findings will be discussed in relation to previous aging studies into habitual and goal-directed control, as well as other cognitive impairments, challenges that older adults may face in everyday life, and to the neurobiological basis of the developmental pattern of goal-directed action across the lifespan.


Assuntos
Envelhecimento/fisiologia , Condicionamento Operante/fisiologia , Objetivos , Deficiências da Aprendizagem/fisiopatologia , Adolescente , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Discriminação Psicológica/fisiologia , Feminino , Humanos , Masculino , Memória de Curto Prazo/fisiologia , Estimulação Luminosa , Desempenho Psicomotor , Adulto Jovem
5.
Brain Cogn ; 78(3): 206-17, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22261226

RESUMO

The ability to flexibly adapt to the changing demands of the environment is often reported as a core deficit in fragile X syndrome (FXS). However, the cognitive processes that determine this attentional set-shifting deficit remain elusive. The present study investigated attentional set-shifting ability in fragile X syndrome males with the well-validated intra/extra dimensional set-shifting paradigm (IED) which offers detailed assessment of rule learning, reversal learning, and attentional set-shifting ability within and between stimulus dimensions. A novel scoring method for IED stage errors was employed to interpret set-shifting failure in terms of repetitive decision-making, distraction to irrelevance, and set-maintenance failure. Performance of FXS males was compared to typically developing children matched on mental age, adults matched on chronological age, and individuals with Down syndrome matched on both mental and chronological age. Results revealed that a significant proportion of FXS males already failed prior to the intra-dimensional set-shift stage, whereas all control participants successfully completed the stages up to the crucial extra-dimensional set-shift. FXS males showed a specific weakness in reversal learning, which was characterized by repetitive decision-making during the reversal of newly acquired stimulus-response associations in the face of simple stimulus configurations. In contrast, when stimulus configurations became more complex, FXS males displayed increased distraction to irrelevant stimuli. These findings are interpreted in terms of the cognitive demands imposed by the stages of the IED in relation to the alleged neural deficits in FXS.


Assuntos
Atenção/fisiologia , Síndrome do Cromossomo X Frágil/psicologia , Reversão de Aprendizagem/fisiologia , Enquadramento Psicológico , Adulto , Cognição/fisiologia , Tomada de Decisões/fisiologia , Feminino , Humanos , Deficiência Intelectual/psicologia , Masculino , Testes Neuropsicológicos
6.
Neuroscience ; 486: 103-125, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33516775

RESUMO

Detecting errors in one's own and other's actions is a crucial ability for learning and adapting behavior to everchanging, highly volatile environments. Studies in healthy people demonstrate that monitoring errors in one's own and others' actions are underpinned by specific neural systems that are dysfunctional in a variety of neurological disorders. In this review, we first briefly discuss the main findings concerning error detection and error awareness in healthy subjects, the current theoretical models, and the tasks usually applied to investigate these processes. Then, we report a systematic search for evidence of dysfunctional error monitoring among neurological populations (basal ganglia, neurodegenerative, white-matter diseases and acquired brain injury). In particular, we examine electrophysiological and behavioral evidence for specific alterations of error processing in neurological disorders. Error-related negativity (ERN) amplitude were reduced in most (although not all) neurological patient groups, whereas Positivity Error (Pe) amplitude appeared not to be affected in most patient groups. Also theta activity was reduced in some neurological groups, but consistent evidence on the oscillatory activity has not been provided thus far. Behaviorally, we did not observe relevant patterns of pronounced dysfunctional (post-) error processing. Finally, we discuss limitations of the existing literature, conclusive points, open questions and new possible methodological approaches for clinical studies.


Assuntos
Potenciais Evocados , Doenças do Sistema Nervoso , Eletroencefalografia , Potenciais Evocados/fisiologia , Humanos , Aprendizagem , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia
7.
Neuropsychologia ; 47(1): 145-57, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18761363

RESUMO

Basal ganglia structures comprise a portion of the neural circuitry that is hypothesized to coordinate the selection and suppression of competing responses. Parkinson's disease (PD) may produce a dysfunction in these structures that alters this capacity, making it difficult for patients with PD to suppress interference arising from the automatic activation of salient or overlearned responses. Empirical observations thus far have confirmed this assumption in some studies, but not in others, due presumably to considerable inter-individual variability among PD patients. In an attempt to help resolve this controversy, we measured the performance of 50 PD patients and 25 healthy controls on an arrow version of the Eriksen flanker task in which participants were required to select a response based on the direction of a target arrow that was flanked by arrows pointing in the same (congruent) or opposite (incongruent) direction. Consistent with previous findings, reaction time (RT) increased with incongruent flankers compared to congruent or neutral flankers, and this cost of incongruence was greater among PD patients. Two novel findings are reported. First, distributional analyses, guided by dual-process models of conflict effects and the activation-suppression hypothesis, revealed that PD patients are less efficient at suppressing the activation of conflicting responses, even when matched to healthy controls on RT in a neutral condition. Second, this reduced efficiency was apparent in half of the PD patients, whereas the remaining patients were as efficient as healthy controls. These findings suggest that although poor suppression of conflicting responses is an important feature of PD, it is not evident in all medicated patients.


Assuntos
Atenção/fisiologia , Inibição Psicológica , Doença de Parkinson/fisiopatologia , Mascaramento Perceptivo/fisiologia , Desempenho Psicomotor/fisiologia , Idoso , Análise de Variância , Comportamento de Escolha/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia
8.
Neuropsychologia ; 45(7): 1408-19, 2007 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-17178419

RESUMO

Individuals diagnosed with mild cognitive impairment (MCI) show primary deficits in memory and are at increased risk for developing Alzheimer's disease (AD). In light of recent evidence that executive cognitive deficits are common in AD and may be detectable in individuals diagnosed with MCI, we extend these findings to the investigation of response inhibition, an essential aspect of executive cognitive control. Twenty MCI patients and 20 healthy controls (HC) completed an arrow version of the flanker task [Eriksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters upon the identification of target letters in a non-search task. Perception & Psychophysics, 16, 143-149] in which participants responded to a target arrow surrounded by distractors (i.e., flankers) that signaled a same (congruent) or a conflicting (incongruent) response. Reaction time (RT) increased in both groups when flankers signaled an incongruent response, but more so among MCI patients. MCI patients taking a cholinesterase inhibitor showed smaller flanker interference effects than those not taking this medication. Analysis of the flanker effect as a function of the entire RT distribution indicated that MCI patients show increasing interference at the slowest segments of the distribution, a finding that implicates deficient inhibition of the incongruent response [Ridderinkhof, K. R. (2002). Activation and suppression in conflict tasks: Empirical clarification through distributional analyses. In W. Prinz & B. Hommel (Eds.), Common mechanisms in perception and action. Attention & performance, Vol. XIX (pp. 494-519). Oxford: Oxford University Press]. These results suggest that deficits in response inhibition are detectable in MCI patients and merit further investigation as to whether these changes aid prediction of which MCI patients convert to AD.


Assuntos
Transtornos Cognitivos/fisiopatologia , Conflito Psicológico , Inibição Psicológica , Tempo de Reação/fisiologia , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/uso terapêutico , Transtornos Cognitivos/tratamento farmacológico , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tempo de Reação/efeitos dos fármacos
9.
Biol Psychol ; 72(1): 96-109, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16157441

RESUMO

The principal aim of the present study was to clarify how stop-signal modality affected the speed and efficacy of stopping, using ERP components as converging measures of stop processes. Both performance and ERP latency findings suggested faster processing of stop signals in the auditory than visual version of the stop task. The effects of successful versus unsuccessful stopping on the amplitude and topography of N2/P3 components elicited by the stop signals appeared to be largely independent of the modality of the stop signals. Stop signals elicited a fronto-central N2 that was much larger on unsuccessful than successful stop trials in stimulus-locked waveforms. N2 was followed by a P3 component that showed a fronto-central distribution on successful stop trials. P3 elicited on unsuccessful stop trials showed a posterior-parietal focus, but this topography was manifested more clearly in response-locked than stimulus-locked waveforms. A dipole source analyses confirmed these topographical differences of P3, and further showed that the location of the corresponding dipoles remained largely identical across the visual and auditory versions of the stop-signal task. Taken together, the present findings support the suggestion that ERP components in the stop task reflect endogenous aspects of stop-signal processing, such as effective inhibition of responses on successful stop trials and detection of errors on failed inhibition trials.


Assuntos
Cognição/fisiologia , Tempo de Reação , Detecção de Sinal Psicológico , Percepção Visual/fisiologia , Adulto , Eletrodos , Potenciais Evocados/fisiologia , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Lobo Parietal/fisiologia
10.
Psychol Aging ; 15(4): 635-47, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11144323

RESUMO

Young and older adults' control of saccadic eye movements was compared using an antisaccade task, which requires the inhibition of a reflexive saccade toward a peripheral onset cue followed by an intentional saccade in the opposite direction. In 2 experiments, an age-related decline was found in the suppression of reflexive eye movements, as indicated by an increased proportion of saccades toward the cue, and a longer time needed to initiate correct antisaccades. The results from Experiment 2 suggested that older adults' slower antisaccades may be explained partly in terms of increased failures to maintain the cue-action representation at a sufficient activation level. The results suggest that the notion of selective preservation with age of the ability to inhibit spatial responses does not apply to the active inhibition of prepotent spatial responses.


Assuntos
Envelhecimento/fisiologia , Movimentos Sacádicos , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tempo de Reação
11.
Biol Psychol ; 41(1): 29-53, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8562672

RESUMO

The objective of the current experiment was to perform a psychophysiological investigation of the interference effects of global information on the analysis of local information, and vice versa. Subjects' choice reactions to letters at one level of information in a compound letter stimulus were impaired when letters at the other (irrelevant) level signified the opposite response. In the absence of differences in processing speed, global and local information produced symmetrical interference effects. Interference effects did vary, however, as a function of temporal advantage for the processing of information from either level. The individually faster level (be it global or local) interfered with the slower level but was itself relatively immune to such interference by the slower level. Analysis of event-related brain potentials and of the electromyogram revealed that incongruent irrelevant letters induced perceptual conflict but not response competition, thus pointing to a perceptual locus of processing dominance for the faster processed level of information in the compound stimulus.


Assuntos
Atenção/fisiologia , Potenciais Evocados Visuais/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Adolescente , Adulto , Córtex Cerebral/fisiologia , Aprendizagem por Discriminação/fisiologia , Dominância Cerebral/fisiologia , Eletroencefalografia , Eletromiografia , Humanos , Individualidade , Masculino
12.
Biol Psychol ; 54(1-3): 55-106, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11035220

RESUMO

Our understanding of developmental changes in attentional selection in the growing child has been advanced substantially by the results of (a relatively small number of) studies undertaken from a psychophysiological perspective. The basic outcome of these studies is that, in attentional filtering as well as selective set (the two basic paradigms in attention research), the processes necessary for attentional selection are in essence available even to the young child; however, the speed and efficiency of these processes tends to increase as the child grows into an adolescent. Under optimal conditions, filtering is performed at early stages of information processing, but less optimal stimulus characteristics and task requirements may induce a shift in the locus of selection to later processing stages for young children whereas older individuals are better able to preserve their early locus of selection. When early selection is constrained, young children are substantially more sensitive to the adverse effects of response competition. In selective set, sub-optimal conditions lead not so much to a shift in locus of selection processes, but to a shift in the age at which asymptote efficiency is attained. We have proposed hierarchical regression analysis as a useful technique to examine whether age-related differences in attention effects, as observed in specific ERP components and in RT, are reflections of an age effect on a single source of attentional selection or of separate sources that each contribute uniquely to the developmental trends seen in (attention effects on) RT. Re-analyses of existing data demonstrated that (again depending on task specifics) many but not all of the different component processes involved in attentional selection contributed unique variance to the age-related changes in attention effects.


Assuntos
Atenção/fisiologia , Desenvolvimento Infantil/fisiologia , Adolescente , Criança , Pré-Escolar , Humanos , Lactente , Psicofisiologia , Tempo de Reação/fisiologia , Valores de Referência
13.
Biol Psychol ; 45(1-3): 241-61, 1997 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-9083652

RESUMO

The present article addresses the claim that the speed of information processing qualifies as a processing resource. This claim contends that age-related changes in processing speed pertain to all cognitive processes to the same proportional degree. That is, processing speed is compared to the clock speed of a microcomputer: as young children's clock speed increases, the speed of processing in all cognitive processes increases until the adult level is reached. Re-analyses of recent behavioral and psychophysiological data provide evidence against the notion that development is characterized by an increase in children's global clock speed, and refute the claim that processing speed operates as a mental resource on which all cognitive processes depend to the same extent. Rather, the results emphasize the role of inhibitory control in cognitive development, and we consider the relevance of inhibitory development to the issue of age-related changes in processing capacity.


Assuntos
Processos Mentais/fisiologia , Potenciais Evocados , Humanos , Modelos Anatômicos , Tempo de Reação
14.
Biol Psychol ; 45(1-3): 263-82, 1997 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-9083653

RESUMO

The rate of information processing, as revealed in measures of reaction time, slows with advancing age and this slowing is most evident as processing complexity increases. This phenomenon, known as the Age-Complexity effect, has been attributed to general changes in the speed of processing that affect all components of processing indiscriminantly, both within and across tasks in a particular processing domain. That the slowing is thought to be task- and process-independent has led to the additional inference that it reflects reductions in a general processing resource. On the basis of converging evidence identified in a review of both behavioral and chronopsychophysiological studies, we argue that the slowing induced by older age is not generalized, but rather is both task-dependent and process-specific and, as such, cannot be explained in terms of a diminished general processing resource. We close by speculating that elements of the age-induced slowing can be interpreted within the context of the cognitive-energetical model.


Assuntos
Envelhecimento , Cognição , Processos Mentais , Tempo de Reação , Fatores Etários , Potenciais Evocados , Humanos
15.
Neuropsychologia ; 50(5): 583-91, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22223079

RESUMO

Learning to select optimal behavior in new and uncertain situations is a crucial aspect of living and requires the ability to quickly associate stimuli with actions that lead to rewarding outcomes. Mathematical models of reinforcement-based learning to select rewarding actions distinguish between (1) the formation of stimulus-action-reward associations, such that, at the instant a specific stimulus is presented, it activates a specific action, based on the expectation that that particular action will likely incur reward (or avoid punishment); and (2) the comparison of predicted and actual outcomes to determine whether the specific stimulus-action association yielded the intended outcome or needs revision. Animal electrophysiology and human fMRI studies converge on the notion that dissociable neural circuitries centered on the striatum are differentially involved in different components of this learning process. The modulatory role of dopamine (DA) in these respective circuits and component processes is of particular relevance to the study of reward-based learning in patients diagnosed with Parkinson's disease (PD). Here we show that the first component process, learning to predict which actions yield reward (supported by the anterior putamen and associated motor circuitry) is impaired when PD patients are taken off their DA medication, whereas DA medication has no systematic effects on the second processes, outcome evaluation (supported by caudate and ventral striatum and associated frontal circuitries). However, the effects of DA medication on these processes depend on dosage, with larger daily doses leading to a decrease in predictability of stimulus-action-reward relations and increase in reward-prediction errors.


Assuntos
Dopamina/metabolismo , Doença de Parkinson/metabolismo , Aprendizagem por Probabilidade , Recompensa , Idoso , Análise de Variância , Simulação por Computador , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Tomada de Decisões/efeitos dos fármacos , Dopaminérgicos/uso terapêutico , Relação Dose-Resposta a Droga , Feminino , Humanos , Levodopa/farmacologia , Levodopa/uso terapêutico , Masculino , Pessoa de Meia-Idade , Modelos Psicológicos , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/patologia , Estimulação Luminosa , Escalas de Graduação Psiquiátrica , Desempenho Psicomotor/efeitos dos fármacos , Desempenho Psicomotor/fisiologia , Inquéritos e Questionários
16.
Behav Brain Res ; 228(1): 82-6, 2012 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22155477

RESUMO

Increasing evidence suggests that the control of retrieval of episodic feature bindings is modulated by the striatal dopaminergic pathway. The present study investigated whether this may reflect a contribution from the ventral or the dorsal part of the striatum. Along the lines of the overdose hypothesis in Parkinson's disease (PD), functions known to rely on the dorsal striatum are enhanced with dopaminergic medication, while operations relying on the ventral circuitry are impaired. We found that partial mismatches between present and previous stimulus-response relations are, compared to control participants, abnormally low OFF DA medication and normalized ON DA medication. The results suggest that the dorsal striatum, but not (or not so much) the ventral striatum, is driving the flexible control of retrieval of stimulus-response episodes.


Assuntos
Agonistas de Dopamina/farmacologia , Doença de Parkinson/psicologia , Desempenho Psicomotor/efeitos dos fármacos , Idoso , Gânglios da Base/efeitos dos fármacos , Gânglios da Base/fisiologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/fisiologia , Agonistas de Dopamina/administração & dosagem , Agonistas de Dopamina/uso terapêutico , Neurônios Dopaminérgicos/fisiologia , Feminino , Humanos , Masculino , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/fisiopatologia , Desempenho Psicomotor/fisiologia
17.
Clin Neurophysiol ; 123(7): 1309-18, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22192499

RESUMO

OBJECTIVE: The present study investigated involuntary change detection in a two-tone pre-attentive auditory discrimination paradigm in order to better understand the information processing mechanisms underlying attention deficits in fragile X syndrome (FXS) males. METHODS: Sixteen males with the FXS full mutation and 20 age-matched control participants (mean age 29 years) were presented with series of auditory stimuli consisting of standard and deviant tones while watching a silent movie. RESULTS: Brain potentials recorded to the tones showed that N1 and P2, sensory evoked potentials, were significantly enhanced in FXS compared to age-matched control participants. In contrast to controls, the N1 to standard tones failed to show long-term habituation to stimulus repetition in FXS. Additionally, both mismatch negativity and P3a generation, reflecting automatic change detection and the involuntary switch of attention, respectively, were significantly attenuated in FXS males. CONCLUSIONS: The current study demonstrates that auditory stimulus discrimination in the FXS brain is already compromised during the pre-attentive stages of information processing. Furthermore, the apparent pre-attentive information processing deficiencies in FXS coincide with a weakness in the involuntary engagement of attentional resources. SIGNIFICANCE: The stimulus-driven information processing deficiencies in FXS might compromise information processing in several domains and, thus, present a key-deficit in FXS neurocognition.


Assuntos
Limiar Auditivo/fisiologia , Encéfalo/fisiopatologia , Eletroencefalografia , Potenciais Evocados Auditivos/fisiologia , Síndrome do Cromossomo X Frágil/fisiopatologia , Estimulação Acústica , Adolescente , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Mapeamento Encefálico , Estudos de Casos e Controles , Humanos , Masculino , Pessoa de Meia-Idade , Discriminação da Altura Tonal/fisiologia , Tempo de Reação/fisiologia , Adulto Jovem
18.
Clin Neurophysiol ; 123(4): 720-9, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21958658

RESUMO

OBJECTIVE: This study examined whether attention deficits in fragile X syndrome (FXS) can be traced back to abnormalities in basic information processing. METHOD: Sixteen males with FXS and 22 age-matched control participants (mean age 29 years) performed a standard oddball task to examine selective attention in both auditory and visual modalities. Five FXS males were excluded from analysis because they performed below chance level on the auditory task. ERPs were recorded to investigate the N1, P2, N2b, and P3b components. RESULTS: N1 and N2b components were significantly enhanced in FXS males to both auditory and visual stimuli. Interestingly, in FXS males, the P3b to auditory stimuli was significantly reduced relative to visual stimuli. These modality differences in information processing corresponded to behavioral results, showing more errors on the auditory than on the visual task. CONCLUSIONS: The current findings suggest that attentional impairments in FXS at the behavioral level can be traced back to abnormalities in event-related cortical activity. These information processing abnormalities in FXS may hinder the allocation of attentional resources needed for optimal processing at higher-levels. SIGNIFICANCE: These findings demonstrate that auditory information processing in FXS males is critically impaired relative to visual information processing.


Assuntos
Atenção/fisiologia , Córtex Auditivo/fisiopatologia , Síndrome do Cromossomo X Frágil/fisiopatologia , Síndrome do Cromossomo X Frágil/psicologia , Córtex Visual/fisiopatologia , Estimulação Acústica , Adolescente , Adulto , Envelhecimento/fisiologia , Percepção Auditiva/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Potenciais Evocados Auditivos/fisiologia , Potenciais Evocados Visuais/fisiologia , Síndrome do Cromossomo X Frágil/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Análise de Regressão , Transtornos de Sensação/etiologia , Transtornos de Sensação/fisiopatologia , Transtornos de Sensação/psicologia , Percepção Visual/fisiologia , Adulto Jovem
19.
Front Hum Neurosci ; 5: 30, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21519377

RESUMO

Recently, the subthalamic nucleus (STN) has been shown to be critically involved in decision-making, action selection, and motor control. Here we investigate the effect of deep brain stimulation (DBS) of the STN on reward-based decision-learning in patients diagnosed with Parkinson's disease (PD). We determined computational measures of outcome evaluation and reward prediction from PD patients who performed a probabilistic reward-based decision-learning task. In previous work, these measures covaried with activation in the nucleus caudatus (outcome evaluation during the early phases of learning) and the putamen (reward prediction during later phases of learning). We observed that stimulation of the STN motor regions in PD patients served to improve reward-based decision-learning, probably through its effect on activity in frontostriatal motor loops (prominently involving the putamen and, hence, reward prediction). In a subset of relatively younger patients with relatively shorter disease duration, the effects of DBS appeared to spread to more cognitive regions of the STN, benefiting loops that connect the caudate to various prefrontal areas importantfor outcome evaluation. These results highlight positive effects of STN stimulation on cognitive functions that may benefit PD patients in daily-life association-learning situations.

20.
Res Dev Disabil ; 31(2): 426-39, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19939624

RESUMO

The present study examined the cognitive profile in Fragile X Syndrome (FXS) males, and investigated whether cognitive profiles are similar for FXS males at different levels of intellectual functioning. Cognitive abilities in non-verbal, verbal, memory and executive functioning domains were contrasted to both a non-verbal and verbal mental age reference. Model-based cluster analyses revealed three distinct subgroups which differed in level of functioning, but showed similar cognitive profiles. Results showed that cognitive performance is particularly weak on measures of reasoning- and performal abilities confined to abstract item content, but relatively strong on measures of visuo-perceptual recognition and vocabulary. Further, a significant weakness was found for verbal short-term memory. Finally, these results indicated that the choice of an appropriate reference is critically important in examining cognitive profiles. The pattern of findings that emerged from the current cognitive profiling of FXS males was interpreted to suggest a fundamental deficit in executive control.


Assuntos
Transtornos Cognitivos/fisiopatologia , Função Executiva , Síndrome do Cromossomo X Frágil/fisiopatologia , Memória de Curto Prazo , Reconhecimento Visual de Modelos , Adolescente , Adulto , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Síndrome do Cromossomo X Frágil/diagnóstico , Síndrome do Cromossomo X Frágil/psicologia , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/fisiopatologia , Deficiência Intelectual/psicologia , Testes de Inteligência , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Psicometria , Índice de Gravidade de Doença , Comportamento Verbal , Vocabulário , Adulto Jovem
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